Standard Alloy 688 (nominal composition of 73.5% Cu, 22.7% Zn, 3.4% Al and 0.4% Co) is well known for its combination of high strength, good formability and ease of processing. Alloy 688 is widely utilized as a material for springs, switches, contacts, relays, drawn and fabricated parts. It is also known, however, that Alloy 688 suffers from having poor machinability characteristics. For example, the machinability rating of Alloy 688, when compared to a rate of 100 for Free Cutting Brass, is 20.
It is well known that additions of lead tend to improve the machinability properties of several copper base alloy systems. These particular alloys suffer from the disadvantage that they possess low strength properties and are not easily hot workable. It has not been known before that lead additions to both standard and modified Alloy 688, which is well known as a high strength alloy, would significantly improve its machinability.
Accordingly, it is a principal object of the present invention to improve the machinability properties of standard and modified Alloy 688.
It is an additional object of the present invention to improve the machinability properties as above through the use of alloying elements and not any particular processing.
Further objects and advantages of the present invention will become apparent from a consideration of the following specification.